Casing insulator



FIG. 1 is a front, perspective view of the casing insulator of the invention;

FIG. 2 is a front end view of the casing insulator of the invention, the rear end view being a mirror image thereof;

FIG. 3 is a top view of the casing insulator of FIG. 1; and,

FIG. 4 is a view of the casing insulator turned on its side.

The broken line showing is for the purpose of illustrating environmental structure, which forms no part of the claimed design. 

The ornamental design for a casing insulator, as shown and described. 